Heat exchanger



F- FRQHLICH HEAT EXCHANGER Filed Jan. 22, 1962 Dec. 28, 1965 mm ||l|l w I I l l I 1 l n y Ill? 0 r 4 T2" l l l I l l i I I I l l l l l l l II F H\ W I I I l l l l l 11 wuwfim %MW% 1 B M FRANKLIN FRdHL/CH INVENTOR.

BY m 8 M ATTORNEY,

United States Patent O 3,225,823 HEAT EXCHANGER Franklin Friihlich, St. Leonhardstrasse 39, St. Gallen, Switzerland Filed Jan. 22, 1962, Ser. No. 167,816 Claims priority, application Switzerland, Feb. 27, 1961, 2,363/61 3 Claims. (Cl. 165-69) This invention relates generally to a heat exchanger, and more particularly to a heat exchanger provided with improved means for mounting a stack of brittle heat exchanger elements within a housing.

In my prior Swiss Patent No. 283,884 a heat exchanger unit is disclosed which consists of a stack of parallel, technical silicate plates that are spaced by the inter-position of spacer strips. The spacer strips between each pair of plates. are parallel and spaced, and the spacer strips between alternate pairs of plates are arranged at an angle with respect to each other. In this manner, separate channels are defined between alternate pairs of plates for the passage of separate heat exchanging fluids.

In the past, such a heat exchanger unit was mounted in a housing with the plates lying in horizontal planes. Consequently, sealing pressure forces between the plates and the spacer strips were obtained as a result of the weights of the various elements. Additional sealing forces were obtained by the application of loads upon a tension plate seated upon the upper plate of the stack.

The object of the present invention is to provide tensioning means for pressing together the elements of a heat exchanger unit the parallel, spaced plates of which are arranged at an angle relative to the horizontal. In the preferred embodiment of the invention described below, the brittle, technical silicate plates lie in parallel vertical planes.

. According to the invention, the end plates of the heat exchanger unit are supported by rigid tension plates connected with the heat exchanger housing walls for movement in the-longitudinal direction of the stack. Elastic meansfor example, layers of a resilient, compressible material such as rubberare arranged contiguously between the tension plates and the housing side walls parallel therewith. Prior to mounting of the heat exchanger unit in the housing, the tension plates are moved outwardly toward the housing walls to compress the resilient layers. After the space between the tension plates is substantially filled by the stack of plates and spacer strips, the holding forces on the tension plates are progressively released. Owing to the expansion of the compressed resilient layers, the tension plates are uniformly pressed with considerable force against the opposite ends of the stack. The axial compressive force developed in the stack by the tension plates causes the heat exchanger elements to be pressed together in tight sealing engagement.

In accordance with one feature of the invention, the means for displacing the tension plates outwardly toward the housing walls comprise bolts having horizontal portions that extend through aligned openings in the tension plates, the resilient layers, and the housing walls. Adjusting nuts are threadably mounted upon the free ends of the bolt shank portions. In order that the tension plates have planar surfaces in contiguous engagement with the end heat exchanger plates of the stack, the head porions of the bolts are fiat and are recessed in the tension plates.

As a result of the uniform compressive loading of the heat exchanger unit and its resilient mounting in the housing, the development of breakage stresses in the brittle elementsas might be caused by thermal expansion and 3,225,823 Patented Dec. 28, 1965 contraction of the housing elements, or the application of impact forces on the housing, for exampleis avoided.

Other objects and advantages of the invention will become apparent from a study of the following specification when considered in conjunction with the accompanying drawing in which:

FIG. 1 is a vertical section taken along line 11 of FIG. 2; and

FIG. 2 is a vertical section taken along line 22 of FIG. 1.

Referring to the drawing, the heat exchanger includes a housing 11 having front and rear Walls 11a and 11b, respectively, a pair of side walls 11c and 1111, a bottom wall 12, and a top wall 13. Front wall 11a is provided with upper and lower openings 14 and 15, respectively, and side wall 11d is provided with upper and lower openings 16 and 17, respectively. Horizontal dividing wall 18 extends inwardly from wall 11d intermediate openings 16 and 17, and curved baffles 19 extend inwardly from side wall 11c (see FIG. 2)

Horizontal supporting beams 23 extend between the front and rear walls and supportby means of resilient rubber strips 24the heat exchanger unit 20. This unit consists of a stack of parallel heat exchanger plates 30 formed of a technical silicate, such as glass. Hozizontal spacer strips 31 are arranged between alternate pairs of plates and vertical spacer strips 32 are' arranged between the remaining pairs of plates. The spacer strips are also formed of a technical silicate. Rigid metal tension plates are arranged in contiguous engagement with the end heat exchanger plates of the stack, and layers 38 of a resilient, compressible material, such as rubber, are arranged contiguously between the tension plates and housing walls 11a and 11b, respectively. Bolts 34, having head portions recessed in the tension plates, extend through aligned openings in the tension plates 33, the resilient layers 38,

the housing walls 11a and 11b, respectively, and the re inforcing angle beams 35 mounted thereon. Nuts 37, having operating handles 36, are threadably mounted upon the free ends of the bolts.

Stability is imparted to the heat exchanger unit by the pressure beams 26 that rest on resilient strips 25 supported by the upper edges of the plates. Upper and lower horizontal partition walls 27 and 22 are supported intermediate beams 26 and 23, respectively, and the housing side walls as shown in FIG. 2. Sealing strip 28, mounted on the free extremity of horizontal dividing wall 18, is in sealing engagement with the edges of the heat exchanger plates. In the upper portion of the heat exchanger chamber, a fluid spray tube 40 is mounted between walls 11a and 11b.

Assembly of the heat exchanger Assuming that upper wall 13, beams 26, and heat exchanger unit 20 are absent from the housing, nuts 34 are tightened upon their respective bolts to draw the tension plates 33 against their respective housing walls, thus compressing the intermediate resilient layers 38. The heat exchanger unit is now lowered into the housing until it rests upon elements 23 and 24. It is important to note that the number of heat exchanger plates and spacing strips is such that the longitudinal dimension of the stack substantially equals the distance between the tension plates. Nuts 34 are now loosened upon their bolts with the result that the resilient layers 38 expand to displace tension plates 33 inwardly, whereby axial compressive forces are developed in the stack. Owing to the recessing of the bolt heads in the tension plates, a planar supporting surface is afforded the end heat exchanger plates of the stack. The uniform expansion of resilient layers 38 causes the axial compressive load to be equally distributed transversely across the stack with the result that the development of breakage stresses in the brittle heat exchanger elements is avoided. The axial compression of the heat exchanger unit caused by the expansion of layers 38 effects tight sealing contact between the plates and the spacing strips.

Pressure rails 26 are now mounted upon resilient strips 25 on the upper edges of the heat exchanger plates, wall 27 and tube 40 are mounted in the housing as shown, and top wall 13 is lowered into position to close the heat exchanger chamber.

Operation In operation, a first heat exchanging fluid medium M enters the heat exchanger chamber via opening 14 and passes downwardly between alternate pairs of plates through the channels defined between vertical spacer strips 32. This first fluid is exhausted from the chamber via outlet 15 as shown by the arrows in FIG. 1.

Referring to FIG. 2, a second heat exchanging fluid M enters the chamber via opening 17 and passes through those horizontal channels (defined between alternate pairs of plates by horizontal spacer strips 31) that lie below horizontal dividing wall 18. This second fluid is deflected upwardly by the lower baflle 19 and horizontally backwardly by the upper bafile 19, whereby the second medium passes through those horizontal passages that lie at a greater elevation than dividing wall 18. Since the first medium passes vertically between alternate pairs of plates and the second medium passes horizontally between the remaining plates, heat transfer between the two media is readily accomplished.

By means of the spray tube 40, cleaning or temperature modifying fluids may be sprayed downwardly between alternate pairs of plates via the vertical channels defined between spacer strips 32.

As a consequence of the resilient manner in which heat exchanger unit 20 is mounted in the housing, the transmittal of breakage stressescaused by thermal expansion or contraction of the housing elements or by external forces applied to the housing, for example-to the brittle heat exchanger plates is avoided.

Although the invention has been described in connection with an apparatus in which the plates of the heat exchanger unit are arranged in vertical planes, it is apparent that the inventive concept is applicable equally as well to installations in which the stack is mounted with its longitudinal axis at an angle to the horizontal. Other modifications may be made in the apparatus described without deviating from the invention set forth in the following claims.

What is claimed is:

1. A heat exchanger, comprising housing means including at least one vertical wall defining a chamber;

a stack of separable, parallel brittle heat exchanger plates mutually spaced by spacing strips;

means supporting said stack in said housing upon the edges of said plates, said plates being parallel with and spaced from said vertical wall, said supporting means including a rigid metal tension plate spaced from said vertical wall and contiguously engaging one end of said stack, and means supporting the other end of said stack;

resilient means biasing said tension plate solely in a first direction to apply a longitudinal compressive force upon said stack of plates, said resilient means comprising a layer of an elastic, compressible material intermediate and contiguous with said housing wall and said tension plate;

and screw means connected between said housing and said tension plate and extending through said elastic layer for displacing said tension plate in the opposite direction to reduce the compressive force applied to the stack by said resilient means.

2. Apparatus as defined in claim 1 wherein said screw means comprises a bolt having a head portion mounted in a recess in said tension plate and a shank portion extending through aligned openings in said resilient layer and said housing wall, and a nut threadably mounted on said shank on the opposite side of said housing wall from said tension plate.

3. Apparatus as defined in claim 1 wherein said means supporting the other end of said stack comprises a second rigid tension plate contiguously engaging said other end of the stack, second resilient means arranged between said second tension plate and said housing for References Cited by the Examiner UNITED STATES PATENTS 10/1947 Kintner 257-245] 3/1960 Fohrhalty et al. 69

ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, Assistant Examiner. 

1. A HEAT EXCHANGER, COMPRISING HOUSING MEANS INCLUDING AT LEAST ONE VERTICAL WALL DEFINING A CHAMBER; A STACK OF SEPARABLE, PARALLEL BRITTLE HEAT EXCHANGE PLATES MUTUALLY SPACED BY SAPCING STRIPS; MEANS SUPPORTING SAID STACK IN SAID HOUSING UPON THE EDGES OF SAID PLATES, SAID PLATES BEING PARALLEL WITH AND SPACED FROM SAID VERTICAL WALL, SAID SUPPORTING MEANS INCLUDING A RIGID METAL TENSION PLATE SPACED FROM SAID VERTICAL WALL AND CONTINUOUSLY ENGAGING ONE END OF SAID STACK, AND MEANS SUPPORTING THE OTHER END OF SAID STACK; RESILIENT MEANS BIASING SAID TENSION PLATE SOLELY IN A FIST DIRECTION TO APPLY A LONGITUDINAL COMPRESSIVE FORCE UPON SAID STACK OF PLATES, SAID RESILIENT MEANS COMPRISING A LAYER OF AN ELASTIC, COMPRESSIBLE MATERIAL INTERMEDIATE AND CONTIGUOUS WITH SAID HOUSING WALL AND SAID TENSION PLATE; AND SCREW CONNECTED BETWEEN SAID HOUSING AND SAID TENSION PLATE AND EXTENDING THROUGH SAID ELASTIC LAYER FOR DISPLACING SAID TENSION PLATE IN THE OPPOSITE DIRECTION TO REDUCE THE COMPRESSIVE FORCE APPLIED TO THE STACK BY SAID RESILIENT MEANS. 